﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Inspired.Euler
{
    /// <summary>
    /// Find the greatest product of five consecutive digits in the 1000-digit number
    /// </summary>
    public static class Problem008
    {
        /// <summary>
        /// Discover the largest product of five consecutive digits in the 1000-digit number.
        /// </summary>
        [EulerProblem(8, Title = "Discover the largest product of five consecutive digits in the 1000-digit number.")]
        public static long Solve()
        {
            List<int> numbers = (
                "73167176531330624919225119674426574742355349194934" +
                "96983520312774506326239578318016984801869478851843" +
                "85861560789112949495459501737958331952853208805511" +
                "12540698747158523863050715693290963295227443043557" +
                "66896648950445244523161731856403098711121722383113" +
                "62229893423380308135336276614282806444486645238749" +
                "30358907296290491560440772390713810515859307960866" +
                "70172427121883998797908792274921901699720888093776" +
                "65727333001053367881220235421809751254540594752243" +
                "52584907711670556013604839586446706324415722155397" +
                "53697817977846174064955149290862569321978468622482" +
                "83972241375657056057490261407972968652414535100474" +
                "82166370484403199890008895243450658541227588666881" +
                "16427171479924442928230863465674813919123162824586" +
                "17866458359124566529476545682848912883142607690042" +
                "24219022671055626321111109370544217506941658960408" +
                "07198403850962455444362981230987879927244284909188" +
                "84580156166097919133875499200524063689912560717606" +
                "05886116467109405077541002256983155200055935729725" +
                "71636269561882670428252483600823257530420752963450").ToCharArray()
                .Select(i => (int)Char.GetNumericValue(i)).ToList();

            List<int> products = new List<int>();
            for(int i=0; i < numbers.Count; i++)
            {
                products.Add(numbers.Skip(i).Take(5).Aggregate(1, (seed, item) => seed *= item));
            }

            return products.Max();
        }
    }
}
